Fluted shank fastener



Patented ug. 'i fg' i 1 Aflfiilfllfli SHANK FASTENER the ventrance of the fastener but, lilling faction@y the -upperfsides Aof Y ;tl'ie'iplastic r-lfnitton:in-which the- V fi'flnte'sofjthe taclgrest'are forcedfageinstthe ont'ihnation'in art.' V5 barbsonthenndersides of theseutesg-whichA v cut-'into-the plastic wallsg. strongly ankv 'flresistingft-he `-turning' of `the tackin the button rfluted shankfastener shownirin aieni'application ffeicient3fastener.'

filed bymeen 263,519.41. bearing'Serial'lfon; `10 Stillanotherjobject ofthe inventionisto `pro- The present invention "relates prticularly`-to the mannerinwhi'ch the bar bsare'positionedanci amum'areayofjc' ntactbetween the fastener headY vide av fastener Yhavingja small radius *dome n hecenterof its head tothus provide aj miniformedontheheneainutessogthat'whentheres-1.1 and the-anvilofjthefentaching machine during Vl teneri has oncefbeen driveninttheopeningl 'in-1515 theAv buttonattaching opeation. the fasthe receptive button} it"will take af al# reater 1 1 i tener' can'ffreely partially rotate whenthe biitton exerted on'` an attachedgarfirientbiitton'. 'whiohiffa'stenen ofcourse, Vpiercesjthe ciotliend Still Variotlieiohjet of the inveritinlis to froj "i'cutsfitsvav into'its respective bore -inth'e'button. 4viole a tack fastener especially. Ladjagtecl for Y"is'e1f20 "i"Withfthese "andi 1Aotherobjectsirl viewythe in with buttons `formed'ofBakelitefoi" fotherlfiard "ventioni'fconsists certain new `andinovel ar- Y plastics, in lthehub 'oilwhichhtton thereis `rangements and"combinations'A of'parts as'jwill f forniecl'a receptive lsnioth-hensfe`val`f thobe hereinafter morelfully described and pointed with barbs, ferme @nime heiai respectivefridges or utsf so that necessaryto provideapulligfsti'in of serveral`35V Fig;-Y fieis a:sectional"view vteken on'linefd--l fastening' nieans'forthe butt Still another object of the hundred pounds or'the'bnttonfwhic iifonlg4 not of Fjgyjgy happen' ordinary ALise e th slightly rotate inthe opposite Hirectiq'n frorn Y which it entered andthe barbs will hite i r1't"o }the Fig.- 5wis-a`s'ecmna1 view-mime .5 5 lof Fig. eend- 6 shows et-:button` Wlthrthe `fas tenerhavy Referring now moreperticularly tolthe .drawen istqprb- .Lina andlronthemoment1t0. Fig. 1, where is vide a iiteclfshanl'z` fastener'w iereinueachfilute shown. the fastener gona greatly enlargedfsale i5 Provided Wt'hf Mliu'fl Ofbrbs .therints onsistineofA the metalshank l which isheaded tener, and which b ars'are fcrinefd.` b`,v plowing s wedged` under the head, as rnayl'be clearly-seen of the helices over tol the under sides. or facesoi tion? lof Vthe, sha,n k forms la small radins dome,

their respective helices or utes L f- .the ladlls'ppg plllfposje 1vA lessthenfthfat 'ofthe Y 'In other words, informing" the` harbsno metal 50 contour of the head itselfin orde'r` to provide a is removed, but the metalformingtliefresultant minimum' area of vontfact;A between the` fastener barhs'is plowed o forcedin'thefdesired direction. head and the anviloffthe attaching; machine,

' Vthat theY- depth of the notches-.'onnicksf tofcrm plowing thrdug'i1j-gthene1ica1ridge;

"jt willibe.understoodasjheretofore mentioned that' the' number V*of* helical iluteslnightpe' irl- Q ispositioned onjfan-'anvlorfgettrng gtatjpn center dome is for theY purpose of hiding the joint between the two pieces of metal. The outer groove 5 is for the sake of appearance, and may be dispensed with if desired.

The shank of the fastener is pointed as at 6, while the shank is also uted to provide a series ofhelical ridges 1 and inthe present instance vhaveshown eight ;of these ridges or flutes. l"Itwill be understood at the outsetv that barbs (to be later mentioned) might be increased to increase the 0f*` the number of utes and their holding power of vthe fastener. course, would be passed if the fastener broached vits Way into the button. insteadrof par-tllytturnlv ing when insertedunderpressure; iff fj vIt also might be mentioned here'th'at I have found thatethe outside diameter-oigtheg flutes shouldbe approximately .064" (sixty-four thousandths of anY inch) while the root-diametershould be .044 s .(forty four thousandthsg-,oigan inch m aki ng a depth of Avilutefon: leach, sideof .010 (tenthousandthsofanfinch.) Y The aver'- agediaineter. of 1-,he pinly which; forms the :here

ityrfour' thousandths. -of ammala) swtmtthe nientionedfprovides thefh'ig'l est holding power obtainedwi'thontdanger of breakf; ing a button in rorcingthe gtackrthereing' If a smallerholefboreis so the flutes would cnt .fdeeper'grooves taohing, the hub of thebutton .,Willbrea the .holel is larger,- thenwithusing fthe same* tack it will broachfits Wayfintothebutton inrhave also found that thzepitcn the (helix vis preferably about 39 (thirty degreeslglalthoughj this may be varied rif desired 'in.'t he ,s`am e way that, thenuinber lof flutes maybeincfreasecl,

. thatfit ist.prefrahleato.A uSasiXJ-of these radially :As aisoi mayabeiseemmmg; 1; artertne shank ldges 2,327,556 The groove d in the metal disk bounding theY 5 ing the barbs on the flutes.

flut-es cut'grooves on the inside ofthe hore; only-.1

stead of turning'fandthe. holding powerwillbe; lost. Y'

vis cpassed into "the cuttingstool the. rows of barbs are y in vertical alignment, eachploweor making- 4Vtool lforming a barb wherever itcro'ssesthe edge of: asi-neuen fridge The piowseor tooisafmot 1.65V ytack driven= into 1 creased, the number of barbs.

' It is alsoV true that a cutting tool with more Vbe used for; form-# On the other hand', be decreased, and the' ncking toolsl either increased or decreasedg-but 1 haver1 found inactual practice that a shank with' eightbarbsfgives the greatest@ radial knives than `six might the flutes might 0 holding powerwithou'- having aA tendencyto .breach its Way into the bore of the button.

Although in actual fffbarbs a barb forming tool Vwhich travels a straightnne parallelv with the axis of theptacl; 5f haslmbeen used;.-1it*.f is understood that a barbr `-forrn'irigtoot-following a path in a hein; oppof vsite'to*the'fdhelizvof thehutes might lalsoibe used;- f f tihust,l if the f utes on 'the tack are leftfhan'ded. a

the helix of the barb forming tool will'be rightturnngand withdrawing act I: haYe-found-lait' ,than the diameter the tack', resist *hundred 4eighty -rrsor'degrees while' the' average fgvvastenfrlmdegrees;

i resisting "strength was' o ncj hundred j seventv-ve" 'v i trotation in "attachirn` S vThus-'the average gain was' -resisting power'of the fastener.'

A AS1neretoforemeriticned, thezllrn'it of th nim berfofV helicesfwould bereached just' before the f 60` lthan'rotate and outfits owngrooves; Y

ritinje'd 'here that. the"- standa'rd required ing'tack vbuttons ifsfforjtheptack 1 t o res istr a pulling'jstrain of/about 'One' hundred "lit-might alst-te me tha-button wouldinotwitnastandjthe necessary pullf'to' meettherequirefve5.

be understood that Awher itji :when 'tack'buttons 'are astene which would result in an increase vof y' practice informing these Y i90). degreesgand 'whose "aavraee'degree;Ofrotation pulling, T011 was i 50twenty:eight (28) degrees? 5' slightly overrtwen- @ty-five (25X pounds,j andtit s'thought thatanv manufacture of the fasteners is relatively inexpensive.

Having thus described my invention, what I claim as new and desire to secure by Letters Patent is:

1. A metal fastener including a head, a pointed shank, a plurality of helical flutes defining ridges extending substantially throughout the length of the shank, the ridges of the iiutes being provided with axially extending notches, barbs disposed adjacent the notches and the said barbs extending towards the head of the fastener to thereby add to the holding power of the fastener after being driven into an opening of slightly less diameter than the diameter of the shank of the fastener.

2. A metal fastener including a head, a pointed shank, and a plurality of helical utes defining ridges extending along said shank, the ridges of the flutes being provided with axially extending plowed notches and the displaced metal adjacent the notches forming barbs and the points of the barbs extending towards the head of the fastener to thereby add to the holding power of the fastener after being driven into an opening of slightly less diameter than the diameter of the shank of the fastener.

3. A metal fastener including a head, a shank,

a plurality of helical flutes defining ridges extending along said shank, the ridges of the flutes being provided with a series of plowed notches forming barbs, said barbs extending along lines substantially parallel with the central axis of the shank and disposed on the under surface of the ridges with the points of the barbs directed towards the head of the fastener to thereby add to the holding power of the fastener after being driven into an opening of slightly less diameter than the diameter of the shank of the fastener.

4. A metal fastener including a head, a pointed shank, a plurality of helical flutes defining ridges extending substantially throughout the length of the shank, the ridges of the utes being provided with axially extending notches forming barbs, the said barbs extending towards the head of the fastener and on the under surface of their respective ridges, the said head of the fastener having a central dome shaped portion of less radius than the remainder of the head whereby the fastener may rotate freely when being driven into its receptive opening.

5. A metal fastener including a head, a pointed shank, a plurality of helical flutes defining ridges extending substantially throughout the length of the shank, the ridges of the iiutes being provided with axially extending notches forming resultant barbs, the said barbs extending towards the head of the fastener and on the under surfaces of their respective flutes, the said head of the fastener consisting of a disk through which protrudes the rear end of the shank and the said rear end of the shank being headed in said disk to form a dome shaped portion centrally of the face of the disk whereby the fastener may rotate freely during an attaching operation.

FORREST Gr. PURINTON. 

